VMIACC-5595-208 GE 8端口多模反射内存交换机

VMIACC-5595-208 GE 8端口多模反射内存交换机

vmiacc-5595交换机： 自动旁路有故障或不连贯的反射内存节点。光纤反射内存网由网卡、路由器和光纤三部分组成，其中网卡选择的型号是VMIC公司的VMIPCI-5565，路由器选择的型号是VMIACC-5595。光纤反射内存网的高传输速度为170Mbyte/s，大可支持256个节点。 光纤反射内存网有环形和星形两种构型；实际应用中结合了这两种构型，见图1，其网络结构分为两层，顶层为环形，底层则为星形，系统主控调度计算机和4个路由器形成顶层环形网，各设备计算机连接在路由器上，构成底层节点。

这种混合结构的优点在于：一、由主控计算机发出的系统时钟信息到达各个节点的时间比较短且较为一致，有利于系统设备间的同步运行；二、仿真系统有多种仿真组态方式，每种仿真组态方式需要的设备并不相同，而混合结构光纤反射内存网允许跳过不用的节点，这样某些试验组态下中用不到的设备节点就不需要开机运行。 图 1 系统采用较为便宜的多模光纤，节点间大传输距离为300米，已满足试验室的布线要求。但使用多模光纤时，顶层环形网实际是准环形的，顶层布线必须占用每个路由器的两个端口。 2、半实物仿真系统设计 主控计算机通过光纤反射内存网设置仿真系统的仿真模式和设备配置，负责系统时钟的发布，启动、暂停或终止系统的运行，并监视在光纤反射内存网上的数据交换，从而掌握系统中每台设备的运行状态。

该仿真系统运行时数据吞吐量很大，除了需要考虑基本的硬件因素外，还有考虑通讯协议和信息格式方案，以及软件读取数据的方式，这些都会影响整个光纤反射内存网的运行效率。作为双端内存来工作，本地主机对它的反射内存地址空间进行写操作，该地址空间是本地内存的一个端口。 RFM板自动地将这个新的数据从它的另一个端口传出去，这个端口是连接在环状体系结构的网络上的光纤，工作速率为2.1G波特率。网络中的下一个RFM板接收到这个新的数据，其本地内存将在400ns之内被更新。RFM产品的网络可以大大节省软件开发的费用，因为不需要编写、测试任何的应用代码，也无需编写相应的文档，更无需维护装配信息和解码信息，以及从输入信息中解析数据。软件 是公司可以支配的独立的为昂贵的开销。RFM产品无需软件和学习曲线，将会大大节省产品的上市时间。

VMIACC-5595-208 GE 8端口多模反射内存交换机

Vmiac-5595 switch: Automatically bypass faulty or incoherent reflected memory nodes. Optical fiber reflected memory network consists of network card, router and optical fiber. The model of network card selected is VMIPCI-5565 of VMIC company, and the model of router selected is VMIAC-5595. The fiber reflection memory network has a high transmission speed of 170Mbyte/s and can support 256 nodes. Fiber optic reflection memory network has two configurations: ring and star. In practical application, these two configurations are combined, as shown in Figure 1. The network structure is divided into two layers, the top layer is a ring, and the bottom layer is a star. The system master scheduling computer and four routers form the top layer of the ring network, and each device computer is connected to the router to form the bottom node.

The advantages of this hybrid structure are: first, the time of the system clock information sent by the main control computer to each node is shorter and more consistent, which is conducive to the synchronous operation of the system equipment; Second, the simulation system has a variety of simulation configuration, each simulation configuration requires different devices, and the hybrid structure of the fiber reflection memory network allows to skip unused nodes, so that some of the equipment nodes that are not used in the test group state do not need to be powered on. Figure 1 The system uses relatively cheap multi-mode optical fiber, and the large transmission distance between nodes is 300 meters, which has met the wiring requirements of the laboratory. However, when multi-mode fiber is used, the top ring network is actually quasi-ring, and the top layer wiring must occupy two ports of each router. 2. Semi-physical simulation system design The main control computer sets the simulation mode and equipment configuration of the simulation system through the optical fiber reflection memory network, is responsible for the release of the system clock, starts, suspends or terminates the operation of the system, and monitors the data exchange on the optical fiber reflection memory network, so as to master the operating status of each device in the system.

The data throughput of the simulation system is very large. In addition to the basic hardware factors, the communication protocol and information format scheme, as well as the way of data reading by software, should be considered, which will affect the operation efficiency of the entire optical fiber reflected memory network. Working as a two-ended memory, the local host writes to its reflected memory address space, which is a port of the local memory. The RFM board automatically passes this new data out of its other port, which is an optical fiber connected to the ring architecture network, operating at a rate of 2.1G baud. The next RFM board in the network receives this new data and its local memory is updated within 400ns. The network of RFM products can greatly save the cost of software development, because there is no need to write, test any application code, no need to write corresponding documentation, no need to maintain assembly information and decode information, and parse data from input information. Software is at the disposal of independent companies for expensive expenses. RFM products do not require software or a learning curve, which will significantly reduce time to market.